Open Source Black Box Testing tools

CAL9000 is a collection of browser-based tools that enable more effective and efficient manual testing efforts. Includes an XSS Attack Library, Character Encoder/Decoder, HTTP Request Generator and Response Evaluator, Testing Checklist, Automated Attack Editor and much more.

Acceptance Testing Tools

Acceptance testing tools are used validate the functionality of web applications. Some follow a scripted approach and typically make use of a Unit Testing framework to construct test suites and test cases. Most, if not all, can be adapted to perform security specific tests in addition to functional tests.

Open Source Tools

HtmlUnit - http://htmlunit.sourceforge.net/ - A Java and JUnit based framework that uses the Apache HttpClient as the transport. Very robust and configurable and is used as the engine for a number of other testing tools.

Canoo Webtest - http://webtest.canoo.com/ - An XML based testing tool that provides a facade on top of htmlunit. No coding is necessary as the tests are completely specified in XML. There is the option of scripting some elements in Groovy if XML does not suffice. Very actively maintained.

HttpUnit - http://httpunit.sourceforge.net/ - One of the first web testing frameworks, suffers from using the native JDK provided HTTP transport, which can be a bit limiting for security testing.

Watij - http://watij.com - A Java implementation of WATIR. Windows only because it uses IE for it's tests (Mozilla integration is in the works).

Solex - http://solex.sourceforge.net/ - An Eclipse plugin that provides a graphical tool to record HTTP sessions and make assertions based on the results.

Selenium - http://www.openqa.org/selenium/ - JavaScript based testing framework, cross-platform and provides a GUI for creating tests. Mature and popular tool, but the use of JavaScript could hamper certain security tests.